1. Field of the Invention
The present invention relates to downhole oil and gas well tools and more particularly relates to an improved downhole oil well tool that can be lowered on a wireline into the well bore for removing a gas lift valve, that is stuck in a side pocket mandrel. Even more particularly, the present invention relates to an improved method and apparatus for removing a stuck gas lift valve from a side pocket mandrel in an oil and gas well wherein a tool body is run into the well bore on a wireline and pressure is applied with a valve removal arm to the bottom of the stuck gas lift valve. The valve removal arm movably extends from a retracted position within the tool body housing to an exposed position that allows it to engage the bottom of the gas lift valve during the removal step.
2. General Background
In the production of oil and gas wells, it is known to employ gas lift valves that assist in the transmission of oil and gas products from the surrounding formation to the surface. Injection of pressurized fluids in combination with the gas lift valve accomplishes this task in a manner well known in the art. The gas lift valves are placed at intervals along the well bore (i.e. different elevations).
Gas lift valves are retrievable devices that are placed downhole in a section of well tubing that is called a side pocket mandrel. Side pocket mandrels are known in the art and have been used commercially for a number of years. During operation, gas lift valves are placed inside the side pocket portion of the mandrel. Such valves can typically be used either for continuous or intermittent flow gas lift production.
One particular type of side pocket mandrel uses an orienting sleeve. This orienting sleeve provides precise alignment and insertion of side pocket devices into the mandrel side pocket. For example, the orienting sleeve allows gas lift valves to be accurately positioned with respect to any radial position so that they quickly register into the side pocket of the mandrel.
One company that manufactures and sells gas lift valves and side pocket mandrels is Camco, Incorporated of Houston, Tex. A prior art publication that shows many gas lift valves and side pocket mandrels is the Camco catalog entitled "Gas Lift Product Catalog", copyrighted in about 1987.
In a typical oil and gas well, there can be a number of side pocket mandrels spaced at different elevations within the well. Each of these side pocket mandrels can carry a gas lift valve as is known in the art. In normal well operations, a problem arises when one of the gas lift valves becomes inoperable and stuck so that it can not be serviced or replaced. A common problem that prevents removal of a gas lift valve occurs when the top end portion of the valve becomes either bent or broken. If the gas valve is not broken or stuck, it can be grabbed at its top end and removed. If the top of a gas lift valve becomes broken, such prevents conventional removal with a pulling tool.